MJF6668 Equivalent & Substitute Parts

Part Overview

The MJF6668 is a PNP Darlington bipolar junction transistor manufactured by onsemi, rated for 100 V collector-emitter breakdown voltage and 10 A maximum collector current in a TO-220FP through-hole package. This device is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The MJF6668 delivers 2 W maximum power dissipation with a minimum DC current gain of 3000 at 3 A collector current and 4 V collector-emitter voltage.

Substiute Parts

MJF6668

onsemiIn Stock: 898MJF6668 Datasheet

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BDW94CFTU

onsemiIn Stock: 4474BDW94CFTU Datasheet

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BDW94CFP

STMicroelectronicsIn Stock: 1646BDW94CFP Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MJF6668 are selected based on the following critical parameters that determine functional equivalence:

Mandatory Matching Parameters:

• Transistor Type: PNP - Darlington configuration
• Voltage - Collector Emitter Breakdown: 100 V (minimum requirement)
• Mounting Type: Through Hole
• Package / Case: TO-220-3 Full Pack or compatible variant

Performance Parameters:

• Current - Collector (Ic) (Max): Equal to or greater than 10 A
• Vce Saturation: 3V @ 100mA, 10A (consistent across all candidates)
• Operating Temperature: Minimum 150°C (TJ)

The substitute parts BDW94CFP and BDW94CFTU meet or exceed all mandatory parameters. Both devices maintain the same voltage rating, support higher collector current (12 A), and operate within the required temperature range. The primary differences relate to power dissipation capability, packaging format, and product status (active versus obsolete).

Parameter Comparison

Engineering Selection Recommendations

BDW94CFP (STMicroelectronics) is the primary substitute for the MJF6668. This device maintains identical package format (TO-220FP), supports the same voltage and saturation specifications, and provides higher current capability (12 A versus 10 A). The BDW94CFP is ROHS3 compliant and carries active product status, ensuring long-term availability and supply chain stability. Power dissipation is rated at 33 W, exceeding the MJF6668's 2 W specification. This part is suitable for direct replacement in applications where the original TO-220FP package footprint is required.

BDW94CFTU (onsemi) serves as an alternative substitute, also manufactured by onsemi. This variant uses the TO-220F-3 package format and delivers the highest power dissipation rating (80 W) among all candidates. The BDW94CFTU is ROHS3 compliant and maintains active product status. The primary consideration for this part is package compatibility; the TO-220F-3 format differs from the MJF6668's TO-220FP, requiring verification of PCB footprint and thermal management requirements.

Both substitute parts are REACH unaffected and carry the same ECCN and HTSUS classifications as the original device. Selection between BDW94CFP and BDW94CFTU depends on packaging requirements and thermal design constraints specific to the application.

Frequently Asked Questions (FAQ)

Q: Can the BDW94CFP directly replace the MJF6668 without circuit modifications?

A: Yes. The BDW94CFP maintains identical voltage rating (100 V), saturation characteristics (3V @ 100mA, 10A), and package format (TO-220FP). The higher current rating (12 A) and power dissipation (33 W) provide design margin without requiring circuit changes.

Q: What is the difference between BDW94CFP and BDW94CFTU?

A: Both devices share identical electrical specifications (100 V, 12 A, PNP Darlington). The primary differences are manufacturer (STMicroelectronics versus onsemi), package variant (TO-220FP versus TO-220F-3), and power dissipation rating (33 W versus 80 W). Package selection depends on PCB layout and thermal requirements.

Q: Why does the MJF6668 have a higher DC current gain (3000) than the substitute parts (750)?

A: The DC current gain specifications are measured at different operating points. The MJF6668 is specified at 3 A and 4 V, while the substitute parts are specified at 5 A and 3 V. These differences reflect the measurement conditions rather than fundamental device capability differences. Both configurations are suitable for Darlington applications.

Q: Are the substitute parts RoHS compliant?

A: Yes. Both BDW94CFP and BDW94CFTU are ROHS3 compliant. The original MJF6668 is RoHS non-compliant, making the substitutes preferable for applications requiring regulatory compliance.

Q: Can I use the BDW94CFTU in place of the BDW94CFP?

A: Electrical substitution is valid; however, the package format differs (TO-220F-3 versus TO-220FP). PCB footprint compatibility must be verified before implementation. Both devices are electrically equivalent for the MJF6668 application.

Q: What is the minimum operating temperature for the substitute parts?

A: The substitute parts are specified for a maximum operating temperature of 150°C (TJ). The MJF6668 supports a range of -65°C to 150°C. For applications requiring operation below 0°C, thermal performance verification is necessary.